The novel herpesvirus-like DNA sequences, which were identified in AIDS-related Kaposi's sarcoma (KS) and designated KS associated herpesvirus (KSHV) or human herpesvirus 8 (HHV-8), have been reported to be associated with various forms of KS. Here, we searched for the presence of KSHV sequences in various other skin lesions including premalignant or malignant skin tumors of a total of 69 clinical cases without immunodeficiency due to AIDS or following organ transplantation. Strikingly high rates of detection were obtained for premalignant Bowen's disease and malignant squamous cell carcinoma, accounting for 71.4% and 50%, respectively. A less frequent but as yet high incidence (33.3%) was scored for actinic keratosis, a premalignant epidermal disorder. In contrast, the frequency remained low (16.7%) for another type of proliferative skin lesions of extramammary Paget's disease and non-proliferative skin lesions (dermatitis, morphea, epidermal cyst and scar). These results suggest a close association of KSHV with at least some non-KS malignant and premalignant skin lesions in non-immunocompromised patients.